1. Field of the Invention
The present invention is related to the area of integrated circuit designs. More particularly, the present invention is related to techniques of designing integrated circuits supporting multiple bands of radio frequency (RF).
2. Description of the Related Art
With the evolution of wireless communications, there are many types of standards or protocols being adopted to facilitate wireless communication between devices. Examples of such standards include 802.11a, 802.11b, 802.11g, 802.16d and 802.16e. Depending on actual applications, it is not possible to conclude one standard is better than another standard. As a result, various chips have to be designed, each for one or more standards.
Multiple chips can meet the market needs but increase engineering costs and design cycles. On the other end, integrating all standards in a single chip could potentially increase the die size, resulting in higher cost of the chip. There is, thus, a need for an integrated circuit architecture that integrates functions provided in more than one standard by using common functional blocks so that the resultant chips can support more than one standard without significantly increasing the design complexity and die size.
In a typical application of such baseband chips, there is a RF interface circuit, also referred to as a transceiver, to receive/transmit signals from/to another device via air by means of radio. Such a transceiver shall also be able to handle RF signals in multiple bands. Regardless of whatever standard a type of wireless communication is conducted with, signals may be received or transmitted at different carrier frequencies. Some of the common exemplary carriers include 700 MHz, 2 GHz, 3 GHz, and 5 GHz bands. A device may very well operate in a region that only supports 700 MHz band. The same device may be brought into a region that provides a carrier frequency other than the 700 Mz band. It would be desirable that such a device operates anyway regardless whatever the carrier frequency may be. Thus, there is a need for a transceiver architecture that may support multiple RF bands.